The present invention relates to the art of rotary-linear actuators and more particularly to a rotary-linear actuator system, methods of manufacturing and methods of using a rotary-linear actuator.
Rotary-linear actuators are used in a variety of industrial and manufacturing settings to provide precise, repeatable action(s). There is a need in the field for rotary-linear actuators that provide high accuracy, low weight, large load-carrying capacity, compact size, smooth operation and cost-effectiveness.
The following presents a simplified summary of the invention in order to provide a basic understanding of some aspects of the invention. This summary is not an extensive overview of the invention. It is not intended to identify key or critical elements of the invention or to delineate the scope of the invention. Its sole purpose is to present some concepts of the invention in a simplified form as a prelude to the more detailed description that is presented later.
The present invention relates to a system and method for a rotary-linear actuator having a spindle assembly including a plurality of annular magnets and a plurality of bar magnets. The plurality of annular magnets and the plurality of bar magnets can be mounted on a rotor generally surrounding a support. The rotary-linear actuator can further include a housing assembly having a motor shell, a first set of coils and a second set of coils.
The plurality of annular magnets can be arranged with alternating polarityxe2x80x94substantially half of the annular magnets oriented so that their north poles point radially outward and a substantially equal number oriented so that their north poles point radially inward. Similarly, the plurality of bar magnets can be arranged longitudinally along the rotor with alternating polarityxe2x80x94substantially half of the bar magnets oriented so that their north poles point radially outward and substantially equal number oriented so that their north poles point radially inward.
The first set of coil(s) can comprise one or more coil(s), the density and size chosen based on the application. The first set of coil(s) can be arranged to, when energized, interact with the spindle assembly in a linear mode. Similarly, the second set of coil(s) can comprise one or more coil(s), the density and size chosen based on the application. The second set of coil(s) can be arranged to, when energized, interact with the spindle assembly in a rotational mode.
The spindle assembly can be movable and/or rotatable along a longitudinal axis extending through the rotor. The first set of coil(s) can be arranged to, when energized, interact with at least one of the plurality of annular magnets. Likewise, the second set of coil(s) can be arranged to, when energized, interact with at least one of the plurality of bar magnets. By selectively energizing one or more of the first set of coil(s), a linear motive force can be generated on the spindle assembly by interacting with the field generated by the plurality of annular magnets. Similarly, by selectively energizing one or more of the second set of coil(s), a rotational motive force can be generated on the spindle assembly by interacting with the field generated by the plurality of bar magnets.
Another aspect of the present invention provides for the spindle assembly to include an air bearing allowing an appropriate clearance for the spindle assembly to move. Further, one or more of the annular magnets can comprise a plurality of component magnets.
Another aspect of the present invention provides for the rotary-linear actuator to include a scale assembly, a first encoder and/or a second encoder. For example, the scale assembly can be placed over at least a portion of some of the plurality of bar magnets. The scale assembly can be etched with a pattern of reflective and non-reflective region(s) that are scanned by the first encoder and/or the second encoder to register movement of the spindle assembly. The first encoder can sense a linear position of the spindle assembly. The second encoder can sense a rotational position of the spindle assembly. The first encoder can provide a signal indicative of the linear position of the spindle assembly (e.g., to a control system). The second encoder can provide a signal indicative of the rotational position of the spindle assembly (e.g., to a control system).
Yet another aspect of the present invention provides for methods for manufacturing a rotary-linear actuator having annular magnets and bar magnets and methods of using a rotary-linear actuator having annular magnets and bar magnets.
The following description and the annexed drawings set forth in detail certain illustrative aspects of the invention. These aspects are indicative, however, of but a few of the various ways in which the principles of the invention may be employed and the present invention is intended to include all such aspects and their equivalents. Other advantages and novel features of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the drawings.